What is induced magnetism and how does it occur?

Induced magnetism is the process where a material becomes magnetised when placed in a magnetic field.

Induced magnetism occurs when a piece of unmagnetised magnetic material is placed within a magnetic field. The magnetic field is produced by a magnet and the strength of this field decreases with distance from the magnet. The magnetic field lines are the path that the north pole of a compass needle would follow if placed in the field.

When an unmagnetised material is placed within this magnetic field, the individual magnetic domains within the material, which are normally arranged in a random manner, start to align with the direction of the magnetic field. This alignment of domains creates a net magnetic effect, causing the material to become magnetised. This is known as induced magnetism.

The strength of the induced magnetism depends on the strength of the magnetic field and the properties of the material. Some materials, like iron, are easily magnetised and are known as ferromagnetic materials. Others, like aluminium, are less easily magnetised and are known as paramagnetic materials.

It's important to note that induced magnetism is temporary. Once the magnetic field is removed, the magnetic domains return to their random arrangement and the material loses its magnetism. This is different from permanent magnetism, where the material retains its magnetism even after the magnetic field is removed.

In summary, induced magnetism is a fascinating phenomenon that demonstrates the influence of magnetic fields on certain materials. It's a key concept in the study of electromagnetism and has many practical applications, from the design of electric motors to the operation of magnetic resonance imaging (MRI) machines in medicine.